The cardiac muscles of pig and cattle may contain Cysticercus cellulosae and Cysticercus bovis, respectively.
Kidneys The kidneys are examined first superficially and then after slicing. The sliced parts are kept in normal saline solution so that the parasites may leave the tissues themselves. The kidneys may be found infected with Stephanurus dentatus in pigs and Dioctophyma renale in dogs.
Subcutaneous tissues The skin of the live or dead animals is searched out for the presence of worms and nodules. Parafilaria bovicola in cattle and Parafilaria multipapillosa in horses are found in subcutaneous tissues as thin fragile threads. The subcutaneous nodules are found containing the filarial worms viz.
Body Cavity In cattle and buffaloes, Setaria spp. These are collected in normal saline solution. Muscles Muscles of jaws, tongue, neck, diaphragm, shoulder and thigh are searched for cysticerci, small whitish structures Sarcocystrs in herbivores and pigs and pin point white dots Trichinella spiralis in pigs, dogs and cats only.
Eyes White thread like worms, Thelazia and Setaria spp. Nasal Passages Schistosoma nasalis are searched in nasal granuloma cases. On rare occasions, leeches are found attached to the nasal mucosa.
Fixation It is killing of tissues with a view to keep them near to the living tissues and to prevent autolysis and putrefaction. Autolysis is the lysis or dissolution of the cells by enzymatic action, probably as a result of rupture of lysosome.
The purpose of fixation is defeated if it is carried out a long time after the death of the animal. The ideal aims of fixation are as follows : a To prevent or to arrest autolysis, bacterial decomposition and putrefaction. The fixatives are chemical agents. The protein precipitant fixatives cause shrinkage of the tissues regardless of the osmotic pressure, whereas non-precipitant fixatives do not cause shrinkage.
In general, the lesser is the distortion, better is the fixation. Before fixing, the parasites are stirred vigorously in normal saline solution to remove the mucus or other foreign material adhering to them. The different fixatives are : 1. Its long storage in the cold weather makes the formalin turbid due to formation of paraformaldehyde.
This is polymerization phenomenon and is stopped by the addition of methanol. Such solutions are used again after filtration. Commercial formalin is acidic due to the presence of formic acid in it. It should be neutralised with sodium carbonate or calcium carbonate before use.
Formalin in 0. It fixes proteins and compound fats either as preservative or as fixative and this property is helpful in the demonstration of lipids in frozen sections.
Mercuric chloride It is a protein precipitant and its rate of precipitation decreases after a few millimetres. Thus, pieces of tissues exceeding 5mm in thickness remain over- fixed at the periphery and under-fixed at the centre. Due to these defects, it is not used as fixative. The combining of this fixative with other reagents e. It can be used with many good fixatives. As mercuric chloride corrodes metal, fixatives containing it should never be stored in metal cap containers.
The specimens to be fixed with this fixative should be allowed to remain in it for 24 hrs. Thereafter to remove mercuric chloride from the specimens, they are transferred to a very dilute solution of tincture of iodine for a couple of hrs. Thereafter, they are washed in running water for 24 hrs. Such defects are overcome by pressing the flukes between two microscopic slides, which are kept in position by a cotton thread.
Too much pressure should be avoided to prevent bursting or distortion of the specimens. After 2 hrs. The thick tapeworms like Moniezia, Taenia need to be pressed in between two microscopic slides. All the scolices and thin specimens like Avitellina, Stilesia need more gentle handling. The scolices should preferably be pressed under coverslip No. A minimum of 4 hrs. Preservation This constitutes the keeping of cells and tissues in a life like manner as far as possible.
The agents bringing about this effect are called as preservatives. If the cork comes in contact with alcohol then the tannin dissolves in it and stains the specimens black. In order to avoid it, it is better to store them in glass stoppered phials. Permanent mounts The trematodes and cestodes are stained for making the internal organs visible for proper identification of the species. The stain is usually diluted with distilled water and staining is done for a prolonged period.
The specimens are over stained and later differentiated in 0. Later they are mounted in Canada Balsam. Ectoderm bears numerous cilia. A stylet like spine is present at the anterior end for boring into IH. Germ cells are present. Eye spots present.
Sac like gut present. A pair of cephalic glands penetration gland. Appears like a sac and contains numerous germ cells. An oral sucker present. Two lateral appendages in the posterior half in Fasciola spp.
Numerous germ cells present. A thickening collar is present at the level of oesophagus, behind which there is a birth pore. Body is oval shaped. Oral sucker is at the anterior end of the body. Ventral sucker lies in the middle of the body. Intestine like that of adult, and tail is simple. Amphlstomes Know as "Cercaria pigmentata" Dark brown in colour.
Round or globular in shape. Oral sucker at the anterior end Ventral sucker immediately anterior to the base of the tail. Body pigmented. Tail is simple, short and slender. Two eye spots present in the anterior half of the body. Pigment glands are present. Schistosoma spp. Known as "Furcocercus cercaria" Body is spindle shaped. Pharynx absent. Eye spots absent. Ventral sucker in the middle of the body. Tail is bifurcate distally brevifurcate.
Metacercaria Round encysted forms. Location Bile duct, gall bladder and liver. Sometimes occur in lungs, kidney and uterus as a berrant parasite. Intermediate hosts : Amphibious snails of species like Lymnaea truncatula, and Lymnaea luteola. Morphological characters : 1. It is smaller than, F. Shape : Leaf like, broader anteriorly than posteriorly. At the anterior end there is a cone shaped projection known as cephalic cone followed by a pair of broad shoulders. The posterior portion is 'V shaped.
Oral sucker is terminal and surrounds the mouth opening. The Cuticle bears large numbers of backwardly directed small spines. Ventral sucker present at the level of shoulder. Both oral sucker and ventral sucker are of same size. Intestinal caeca are highly branched only on the lateral sides and reach upto posterior end. Testes are two in number, highly branched, tandem in arrangement and occupy the second and third quarters of the body.
Ovary Is highly branched and present anterior to testes. Vitelline glands consists of large number of fine follicles and are present on either side of entire lateral fields. Uterus is dark in colour and placed anterior to testes and contains large number of yellowish-brown coloured eggs. Fasciola gigantica : Common name, location and host : Same as F. Lymnaea auricularia var reufescence and L. It is larger than F. Cephalic cone is smaller than Fasciola hepatica and shoulder are not distinct.
Ventral sucker is larger than oral sucker. The posterior portion is broadly rounded or- 'U' shaped in nature. Microscopically the intestinal caeca are branched both laterally and medially.
Other morphological characters of Fasciola qigantica are more or less similar to Fasciola hepatica. Fasclolopsis buski Common name : Intestinal fluke of Pig.
These are large and thick flukes, elongate oval, slightly broader posteriorly than anteriorly. Size x mm. Largest trematode of animals. Cephalic cone and shoulders absent. Intestinal caeca simple, convoluted and reach almost to posterior end. Testes are tandem, branched and posterior in position. Ovary is branched and anterior to testes. Vitelline glands occupy the entire lateral fields. Size : x 1. Body is elongated and lencet like, narrow anteriorly and widest behind the middle, delicate and translucent.
Intestinal caeca simple and do not reach upto the posterior end. Testes are slightly lobed and lie in tanden just posterior to the ventral sucker. Ovary, globular in shape and post testicular, just close to posterior testis. Uterus branched and the transverse coils of the uterus occupy most of the space behind the gonads and usually filled with numerous small brownish eggs.
Vitelline glands occupy the middle third of the lateral fields. Eurytrema pancreaticum Common name : Pancreatic fluke. Definitive host : Sheep, Goat, Cattle, Buffalo and occasionally man Location : Pancreatic duct, rarely in bile ducts and duodenum Intermediate hosts : 1st I. Size : x Oral sucker is larger than the ventral. Testes are weakly lobed, horizontal and lie slightly posterior to the level of the sucker.
Ovary weakly lobed, situated near the median line behind the testes. Uterus fills the posterior part of the body. Vitelline glands are follicular and are situated in middle third of the lateral fields. Location : Bile ducts and rarely in intestine and pancreatic ducts.
Intermediate hosts : 1st Snails : Bithynia spp. Size : 7 to 12x1. Shape : small to medium sized flukes with flattened and translucent body which is narrow anteriorly. Suckers weakly developed, situated in anterior third of the body. Intestinal caeca are simple and reach near to the posterior extremity of the body. Ovary small, slightly lobed and anterior to the testes.
The space between the ovary and ventral sucker is filled with ccoiled uterus containing eggs. Vitelline glands consists of series of transversely arranged follicles and occupy the middle third of the lateral fields. They are found as 8 groups on each side. Intermediate hosts : 1st Snail : Bulinus spp. Vivipara spp. Size : 25x5mm 2. Body is flat, transparent, wide posteriorly and tappering anteriorly.
Oral sucker slightly larger than the ventral one, which is situated at the posterior end of the anterior 3rd of the body. Intestinal caeca simple, reach upto the posterior end. Testes are deeply lobulated or branched, tandem in arrangement and present in the posterior 6.
Ovary small, slightly lobed and antero-testicular. Vitellaria are granular aggregations in the lateral fields and extend slightly beyond the middle third of the body. Location : Bursa of fabricius, sometimes oviduct and rarely intestine.
Intermediate hosts : 1st Snail : Gyraulus spp. Size : x mm 2. Shape : Narrow anteriorly and broad posteriorly or pear shaped. Ventral sucker present in the anterior half of the body, and larger than oral sucker. Intestinal caeca simple and reach upto the posterior end.
Testes are horizontal in position and are situated at the middle of the body. Ovary is anterior to testes and highly lobed. Vitelline glands occupy the lateral fields form the level of the ventral sucker to the posterior end of testes. Genital pore opens lateral to oral sucker. It measure 10 to 22 mm long and upto 2. The shape is long and narrow,. Ventral sucker is larger than oral sucker and present in the anterior part of the body.
Testes are tandem in arrangement, elongated and oval, slightly lobed, present behind the middle of the body. Ovary is anterior to testes, oval in shape. Uterine coils with eggs is situated in between the ventral sucker and ovary. Vitellaria consists of coarse follicles and lie in lateral fields extending from the posterior border of the ventral sucker to the posterior end of the body.
Planorbis, Lymnaea and Bulinus spp. Morphological characters: 1. Small size 2. Ventral sucker is absent 3. Testes lie side by side at the posterior end.
Ovary is lobed and placed in between the testes 5. Cirrus sac is present and vagina is half the length of the cirrus sac. Genital pore opens directly behind the oral sucker. Uterus forms more or less regular transverse, coils and extends from the ovary to the posterior of the elongated cirrus sac. Schistosoma 2. Oxientobilharzia Syn. Oxnithobilharzia 3.
Biharziella 4. Bivitellobilharzia 5. Heterobilharzia 6. Trichobliharzia Schistosoma spp. Different veins such as mesenteric vein, nasal vein, portal vein, haemorrhoidal vein etc.
Intermediate hosts Morphological characters Males : 1. It measures 8. Body is irregularly striated and dorsally covered with tubercles. Suckers are weakly developed and situated at the anterior part of cylindrical body near to each other.
Testes are 5 to 7 in groups on each side, situated slightly posterior to genital pore and opposite to ventral sucker. Intestinal caeca bifuracated at the level of ventral sucker, unite at the posterior end of the body and continue as a single caecum. A groove like structure called Gynaecophoric canal present on ventral surface. Females :. It measures 10 to 28 x 0. The shape is elongated and smooth. Spines present in suckers and on posterior end. Ovary oval and situated in the middle of the body.
Uterus occupies about half the distance between ventral sucker and the posterior end,. Vitellaria situated in the posterior part on either side of the intestinal caecum. Orientobilharzia spp. Similar to Schistosoma spp. Rumen and Reticulum Intermediate hosts : Snails : Indoplanorbis exustus. Morphological characters : Immature amphostomes : 1. These are oval shaped or pear shaped, anterior end is narrow with the oral sucker at the tip, and posterior end is broad, with a large posterior sucker.
Intestinal caeca is simple and may or may not reach up to posterior end. Genital organs are not well developed, only faint impressions of ovary, testes and uterus are seen. Mature amphistomes : 1. These are large thick and fleshy, with an oval or pear shaped body. Vental sucker found at the posterior end of the body and known as posterior sucker. These are blood red or brownish in colour when freshly collected. Paramphistomum cervl : 1. It measures about 5 to 13x2 to 5mm. Pear shaped, slightly concave ventrally and convex dorsally with a large subterminal posterior sucker.
Intestinal caeca simple and does not reach upto the posterior end of the body. Testes are slightly lobed and tandem in arrangement. Ovary is posterior to testes.
The vetelline glands are in compact groups in between pharynax and posterior sucker. Cotylophoron cotylophrum: 1. It measures 5 to 13 x 25mm. Ventral sucker is present in posterior part of the body. Intestinal caeca are highly convoluted and reach upto posterior end.
Testes are tandem in position, slightly lobed. Ovary present posterior to testes. The vitelline glands are present in compact groups between the pharynx and posterior sucker.
The genital opening is surrounded by a sucker known as genital sucker, which is prominent and present just behind the bifurcation of intestinal caeca. Gastrothylax crumenifer : 1. It measures 9 to 18 x 5mm. This fluke has a large ventral pouch, which opens anleriorly and extend over the ventral surface upto the posterior sucker. The oral sucker is small and terminal.
Intestinal caeca simple and ends at about the level of anterior border of the testes. Testes are lobed and horizontal in position with the ovary behind them. The posterior sucker is large and terminal and has a raised border. Uterus crosses from right to left at about the middle of the body In a 'S' shaped manner. Carmyerius spatiosus : 1. It measures 9 to 12mm long. Ventral pouch is present.
Testes are horizontal in position. Flschoederius spp. It measures 10 to 20mm long and 3 to 5mm wide. The intestinal caeca are not widely separated and end at a short distance behind the middle of the body. One testes lies dorsal to the other. Uterus runs forward in the mid-line. Gigantocotyle explanatum : Found in the bile duct, liver and gall-bladder of buffaloes and cattle.
Pear shaped, slightly concave ventrally and convex dorsally with a large posterior subterminal sucker. Intestinal caeca simple, convoluted and does not reach upto the posterior end of the body. Tastes are larger than Paramistomurn cervi and diagonal In arrangements. Gastrodiscus spp. It is present in the large and small intestine of equines, pigs and elephants, measures x mm.
Body is divided into two parts, anterior part is more or less cylindrical which is upto 4mm long and 2. The posterior portion is saucer shaped. Posterior sucker is subterminal and smaller than other amphistomes. The testes are lobed, slightly diagonal and lie behind the middle with ovary posterior to them.
The vitelline glands occupy the lateral fields. The genital pore opens at the level of the intestinal bifurcation. Gastrodiscoides hominis caecal fluke of man and colon fluke of pigs 1. Medium size 2. Body divided into two parts. Anterior being smaller than pasterior one and without papillae.
Pyriform in outline and bright reddish in colour. Oral pouches present 5. Pasterior sucker has prominent deep cleft. Pseudodiscus collinsi Colone fluke of equines 1. Medium in size. Body tapering anteriorly and rounded, posteriorly. Intestinal caeca wavy. Oral pouch present 5. Deeply lobed testes placed side by side. The size may vary from a few milimeters to several metres in length containing a few to a large number of segments.
The life cycle of a cestode includes eggs, cysts, occurring In the intermediate hosts and the adult tapeworm in the definitive host. They lack alimentary canal and the food absorption takes place at the microvilli of the Integument. The body is metamerically segemented and consists of three parts viz.
Head scolex , Neck growth region and Body stroblla. The individual segment is called proglottid. The entire chain of segments Is called strobila. Anterior segments without well developed genital organs are immature, middle segments with well developed genital organs are mature and posterior segments containing eggs are gravid segments. Each mature segment may contain one or two sets of genital organs.
Life cycle Is Indirect, except in Hymenolepis nana, and invertebrates or vertebrates act as intermediate hosts. Location and host : Found in the small intestine of sheep, goat, cattle and other ruminants. Morphological characters : Large sized, measuring about cm x 1. Body is thick and broad. The segments are more broad than long. The gravid segments appear like the cooked rice grains.
Scolex : Shape is globular and measure 0. The rostellum and hooks are absent. Mature segment of the Moniezia expansa : The segments are broader than long and each segment contains 2 set of genital organs and the genital pores are bilateral.
Ovary and vitelline glands together form a ring like structure on either side, median to longitudinal excretory canal. Testes are large in number and are scattered throughout the meduallary parenchyma. At the posterior border of each segment, there is a row of interproglottidal glands which are circular in shape and occupies the entire posterior border. Mature segment of Moniezia benedeni : 1. Segments are broader upto 2. Each segment has 2 sets of genital organs and genital pores are bilateral.
Testes are in large number, scattered throughout medullary parenchyma. At posterior border of each segment the interproglottidal glands are arranged In a continuous row and form a band like structure in the middle portion.
Intermediate hosts : : Cysticeraoid develops in oxibatid mites Morphological characters : 1. Adults cm in length and 1. Scolex mm in diameter and is provided with a "Lappet" behind each sucker. Segments are wider than long, each with a single set of reproductive organs. Anoplocephala magna : 1.
Occurs in the small intestine and rearely in stomach of horses. Upto 8Ocm in length and 2. Scolex is large, mm wide, and without lappets. Paranoplocephala mamillana : 1. Occurs in the small intestine and occasionally in the stomach of horses. Measures by mm. Scolex is narrow, the opening of the suckers are slit like. Small intestine of ruminants Oribatid mites Adults may reach 3m in length and 3mm wide.
They are almost cylindrical at the posterior end. Proglottids are short and not distinctly segmented as a result of which they appear as thick white threads. Scolex of Avitellina spp. The scolex measures upto 2mm in diameter, slightly larger than Moniezia scolex.
Shape is globular and has 4 unarmed suckers. Mature segments of Avitelllna spp. Very short and not well defined segments 2. Single set of genitalia. Uterus lies transversely at the middle portion. Excretory canals are prominent with fewer no. Genital pores irregularly alternate, lateral to the excretory canals. Gravid segment of Avitellina spp. These sgement are narrow, more long than broad and are beaded in appearance. Stilesia spp. Intermediate hosts: Oribatid mites Morphological characters : Adults are cm long and upto 2.
Proglottides are short, thin and the body coils like a ribbon. Scolex of Stilesia spp. Globular in shape, Rostellum and hooks are absent and has 4 unarmed suckers. Mature segment of Stilesia spp. Body is weakly segmented. Single set of genitalia with Irregularly alternating genital pores 3. Eleven testes on either side of the excretory canal. Ovary is globular and median to excretory canal. Uterus is dumbbell shaped with two portions united by a transverse duct.
Gravid segment of Stilesia Spp. In the gravid segments all the genital organs are degenerated. Only two paruterine organs are present which contain fertilized eggs. Morphological characters : The adult parasites may be upto 50cm long. Segments are more long than broad and are barrel shaped or cucumber seed shaped. Scolex of D. Dipylidium caninum Mature segment 1. The mature segments are barrel shaped or cucumber seed shaped. Each segment has 2sets of genital organs and genital pores are bilateral.
Ovary and vitelline glands together form a structure on either side of the segments, which looks like bunch of grapes. Testes are in large number and scattered throughout the medullary parenchyma. In gravid segments the eggs are in egg capsules, each containing upto twenty eggs. Intermediate hosts : Gastropod molluscs like Limex, Aripn, Agriolimax spp. Morphological characters 1. Adults are microscopic 0. Rostellum and suckers are armed. Genital pores alternate regularly.
Intermediate hosts : 1 Raillietina cesticilus : Beetles. Neck is absent and the scolex is large, which bears a wide rostellum armed with to small hooks. The suckers are inconspicuous and unarmed. In scolex of Raillietina echinobothrida rostellum is present, which bears number of hooks, arranged in 2 rows. The suckers are circular in outline and are armed with 8 to 10 rows of hooks, all of which are about twice as large as those of R.
Scolex of Rallietina tetragona Scolex is small. Neck is thin. The rostellum has one row of minute hooks. The suckers are oval in shape and armed with 8 to 10 rows of small hooks. It is upto 1. Rostellum has two rows of small hooks, suckers unarmed. Mature segment has two sets of genital organs.
Gravid segment has egg capsules, each containing one egg. Intermediate host : Earthworms Morphological characters : 1. Small worms and roughly triangular in shape, measuring upto 4mm long. Entire body possess about 20 segments and these segments are narrow. Rostellum has spiner shaped hooks arranged in a single row. Testes are about 12 or more and are present in the posterior part of each segment. Genital pores irregularly alternate. Morphological characters : Very thin parasites measuring 13mm by 1mm, Rostellum is retractile, bearing a single circle of hooks.
Suckers are unarmed. Species Tsolium T. Larval Stage Cysticercus cellulosae C. Morphological characters These are large tapeworms and the size may vary from 40mm to 8m.
The mature segments are square shaped. The gravid segments are more long than broad. Taenia scolex : 1. Rostellum is present and it has two rows; of hooks. One row of small another row of large hooks arranged alternately. Suckers are unarmed and shape is globular. Taenia spp. Each segment has one set of genital organs. Ovary is single but bilobed and is present in the posterior part of each segment. Vitelline glands are found in a compact mass, they are placed transversely in the posterior border of the segment, just behind ovary.
Testes are in large number and they are scattered throughout medullary parenchyma. The uterus is a blind sac like tube present longitudinally at the middle of the segment. Gravid segments : 1. The gravid segments are more long than wide. Gravid uterus has 5 to 10 branches on either side. Echinococcus granulosus Location and host: Small intestine of dogs and other carnivores and the larval stage, hydatid cyst, is found in various ungulates and man.
It is a very small parasite. The body has a scolex and 3 to 4 segments. The last segment is the gravide one and it is more than of the length of the body. The mature segments has one set of genital organs. The ovary is single and it is kidney shaped and is placed in the posterior part of segments. Vitelline glands are in a compact mass. They are placed just behind the ovary in the posterior boarders of segments. Testes are about 50 in number and they are scattered throughout medullary parenchyma.
The rostellum has two rows of hooks varying from 30 to 60 In number. Special feature : Tetrathyridia multiplies asexually by longitudinal splitting of the scolex in the second intermediate host as well as definative host. Mesocestoides Iineatus Gravid segments 1. The gravid segments are more or less square shaped.
In the segments all the genital organs are degenerated. Gravid uterus is replaced by an oval shaped paruterine organ containing fertilized eggs. Intermediate host : 1st : Cyclops like Diaptomus gracilis, in which procercoid develops. Morphological characters: Scolex has no suckers but has weakly muscular grooves called bothria. Mature segments are quite different from class Eucestoda with a bilobed ovary in the centre, follicular vitalline glands distributed in the paranchyma along with testes, genital pore at mid ventral portion and a rosette shaped uterus.
Eggs are operculated. Size : micron in diameter Anoplocephala spp. Horse Similar to Moniezia egg. Taenla spp. Hexacanth embryo present.
Size : m Hymenolepls spp. Birds, Rats, Man The egg shell is thin enclosing the hexacanth embryo. Wide space present between egg shell and embryophore Comparatively larger than eggs of Taenla species. Size : m diameter. Dipylidium caninum Dogs and Cats Large oval capsules containing 4 to 20 eggs which have thick but unstriated embryophore. Size : fr m diameter. Dlphyllobothrlum latum Dog, Cat and Man Small oval egg with thin shell Similar to trematode egg Ends appear pointed than round Operculum present Germinal mass undifferentiated and uniformly distributed.
It is the bladder worm stage of Taenia hydatigena. It develops in the peritoneal cavity of sheep, goat and cattle. It has a single scolex, a long neck and a bladder like cavity which is filled with large amount of serous fluid. The cyst wall is thin and translucent. Coenurus cerebralis It is the bladder worm state of Multiceps multiceps or Taenia multiceps. It develops in 1W brain, spinal cord and sometimes In the subcutaneous tissue of sheep and goat.
Shape is nearly circular and the cyst wall is very thin and transparent. Large number of scolices are formed in the inner surface of cyst wall which are very clearly visible from outside. The cyst contains large amount of serous fluid. Hydatid cyst 1. It is the bladder worm stage of Echinococcus granulosus. The size of the cyst may vary and may reach upto 50cm in diameter. Shape is round or spherical.
Cyst wall has 2 layers. Outer layer is very thick and tough, but inner germinal layer is very thin. Scolices are not attached to the inner germinal layer, and present inside the daughter cysts.
These daughter cysts containing the scolices are known as brood capsules. Sometimes these brood capsules may be ruptured so that the scolices are found freely floating in the cyst fluid and these freely floating scolices are known as hydatid sand.
These cysts develop in liver and lungs of all animals, human beings and even birds. Characters : 1. Body is unsegmented, cylindrical and elongate, tapering at both the ends, covered with a tough transparent or translucent cuticle. Body cavity and alimentary canal present. Length of the worms varies from few mm to severel centimetres. Sexes are separate, male parasites are smaller than females. Body wall consists of cuticle, subcuticle and musculature.
In the anterior end some specialized structures such as head bulbs, amphids and alae are presents, which are commonly sensory in function. Life cycle may be direct or indirect.
The males measures 15 to 25cm in length and 3 to 4mm in diameter. Female parasites measure upto 45cm in length and 5mm in diameter. These are very large stout worms. Both ends taper. The cuticle is thick and the worm is fairly rigid 4. The mouth opening has 3lips, one dorsal and 2 subventral. Each lip bears on its inner surface a row of minute denticles. Males cm and females upto 50cm long.
These are rigid stout worms with a large, head. Three lips are conspicuous and are separated by three small intermediate lips. Male tail has small lateral alae. In addition to number of precloacal and post cloacal papillae, a single median papilla occur on the anterior border of cloaca.
Toxocara vitulorum Neoascaris vitulaxum : Common Name : Large round worm of cattle. Location and Host : Small intestine of cattle and buffaloes. Anterior portion is narrower than body. The lips are narrow anteriorly and broad at the base.
The cuticle Is thin and translucent so that the internal organs are visible to outside. Males measure upto 25cm by 5mm and females 30cm by 6mm. Toxocara canis Gross : Common Name : Large round worm of dogs or arrow headed worm. Location and Host : Small intestine of dog and fox. The male parasites measure upto 10cm and female parasites measure upto 18cm. The anterior end has small lips and a large cervical alae.
The anterior end is bent ventrally. The posterior end of the male is slightly coiled and curved and this end has a small caudal alae and a terminal narrow appendage. Male parasites measure 5 to 7cm and female 7. Anterior end has 3 small lips. Both the ends are pointed and cuticle is thick. They are whitish in colour. Ascaridia galli Male posterior end Morphological characters : 1. Tail of the male has a small caudal alae, ten pairs of short and thick papillae.
There is a circular preclocal sucker with thick cuticular rim. Spicules are two in number and of equal size. Heterakis gallinarum : Common Name : Caecal worm of fowls. Males measure mm and females measure mm. There are large lateral alae extending some distance down the sides cf the body. Oesophagus has a strong posterior bulb. Tail of male has a large alae, a prominent precloacal sucker and 12 pairs of papillae.
Spicules are unequal, the right one is long and slender. The left one is short and broad. Vulva lies behind the middle of the body. Males measure mm and females upto mm in length.
The male has one pin-shaped spicule. Adult female is slatey-grey or brownish in colour with a long narrow tail which may be more than 3 times as loog as the rest of the body. Small thin worms. Only females are parasitic. Oesophagus is long and filariform. Uterus contains a single row of eggs. Has a large, deep and oval buccal capsule. Mouth opening surrounded by external and internal leaf crowns.
Two ear-lobe shaped dorsal teeth present at the base of the buccai capsule. The thickening of the internal wall of the buccal capsule forms the dorsal gutter. Head separated from body by a constriction.
Buccal capsule cup shaped and does not have teeth. Dorsal gutter present. Has oval buccal capsule with external and internal leaf crowns. A large dorsal tooth with bifid tip and 2 subventral teeth preset. Males measures At the anterior end cuticle forms a mouth colar which is fairly high.
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